Method of sulphonating by means of gaseous sulphuric acid anhydride



Patented Dec. 8, 193i STES PATENT OFFICE GEORG KALISCHER, F FRANKFORT-ON-THE-MAIN, FRITZ Gfi'NTHER, 0F LUDWIGS- HAFEN-ON-THE-RHINE, KARL KELLER, OF FRANKFORT-ON-THEMAIN, AND JOSE! HETZER, 0F LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, ASSIGNORS TO GENERAL ANILINE WORKS INC., OF NEW YORK, N. Y., A CORPORATION OF DELAWARE I METHOD OF SULPHONATING BY MEANS .OF GASEOUS SUIZPHUBIO AOID' ANH YDRIDE No Drawing. Application filed June 18, 1929, Serial No. 871,954, and in Germany J'uly (l, 1928.

The present invention relates to a process of sulphonating unsaturated fatty acid compounds, for ekample, unsaturated hydroxy fatty acid compounds, in which the sulphonation is carried out by means of gaseous sulphur trioxide in the presence of an organic diluent.

U. S. application Serial No. 197,223 of Fritz Gunther and Josef Hetze'r filed June 7, 1927, relates to a process of producing sulphonic acids derived from non-aromatic hydrocarbons containing more than eight carbon atoms in their molecule, which comprises treating said non-aromatic hydrocarbons and 16 their derivatives with sulphonating agents under energetic conditions. As such a sulphonating agent, among others, sulphuric acid anhydride is named.

Our present invention has for its object 20 a new special method for carrying out this sulphonation process. Our new method comprises treating said hydrocarbons and their derivatives with sulphur trioxide in a gaseous form, advantageously in the presence of an organic diluent, while well stirring and cooling. .Ou'r new process can be easily carried out practically and enables us to measure the quantity of sulphur trioxide so exactly that each desired degree of sulphonation can be obtained. As starting materials to be sulphonated, particularly unsaturated fatty acids which may contain a hydroxy group are to be named. As organic diluents for example,benzene, carbon tetrachloride, perchloroethane, hexachloroethane' and particularly trichloroethylene are suitable.

Advantageously the introduction of S111- phurtrioxide vapormaybe carried out in such a manner, that a current of an inert gas such 9 as air or nitrogen which has been charged with sulphur trioxide vapor, is allowed to enter into the solution of the starting material to be sulphonated.

unsaturated fatty or hydroxy-fatty acid, the intensity of absorption of sulphur trioxide is so high, that it is sufiicient'to allow the sulphur, trioxide. vapor to pass over the well stirred'solution, In this manner the absorp- Especially, when using a solution of antion takes place rapidly and can be interrupted for each desired degree of sulphonation. o

On the other hand, when sulphonating with concentrated sulphuric acid,.an excess thereof is necessary and, when using fuming sulphuric acid, a ballast of sulphuric acid is introduced into the reaction mass. It is an important advantage of our method, that one needs substantiall only of such an amount sulphuric acid'anl iydride aslis suflicient for the sulphonation.

In consequence thereof the products of sulphonation require smaller quantities of caustic alkalies for neutralization.

Whenusing unsaturated fatty acids as starting materials, sulphonated derivatives are obtained containing truesulphonic acid groups attached to a carbon atom, which products are distinguished by particularly valuable properties, especially by an extraordinary resistance to acids and lime; When using unsaturated hydroxy fatty acids, it is necessary, in order to obtain the particularly valuable sulphonation products containing true sulphonic acid groups, to use an amount of sulphur ,trioxide which exceeds the amount v necessary for esterifying the hydroxy groups.

In some cases it maybe an advantage tostart from hydroxy fatty acid derivatives in which the hydroxy groups have been previously esterified by means of, for'instance, sulphuric acid monohydrate or chlorosul phonic acid. But our new method is not only a useful for the introduction of sulphonic acid groups into nonaromatic hydrocarbons, but also for each process of sulphonation. Thus when using only such an amount of sulphu trioxide as just efi'ects theesterification of the hydroxyl groups of hydroxy-fatty acids, products are obtained corresponding in their properties 'with the sulphonated castor oil products of trade. I 'In order to further illustrate our invention the following examples are given, the parts being by weight and all temperatures in centigrade degrees, but it may be understood that our invention is not until a neutral reaction is obtained.

limited to the particular products or reacting conditions mentioned therein.-

Example 1 100 parts of ricinoleic acid are mixed with about 300 parts of carbon tetrachloride; then the solution is cooled down to about 10, 46 parts of sulphur trioxide vapor are while well stirring, allowed to pass over the liquor at a temperature of about 10 to -3, taking care that the absorption of the sulphur trioxide vapor occurs within the aforesaid interval of temperature. When the sulphonation is finished, the compact mass is poured on a small quantity of ice and a dilute caustic soda or sodium carbonate solution is ad rled he salt solution is then separated off and the carbon tetrachloride is removed by distillation in vacua. A brownish colored oil remains which is not decomposed by prolonged boiling with acids.

.Emample Q A slow current, ofsulphur trioxide is allowed to pass over a solution of 100 parts of Castor oil in 150 parts of trichloroethylene at a temperature of about 10 to 3. When parts of S0 have been absorbed, the reaction is interrupted and the reaction mass is poured on a small quantity of ice. It is neutralized at about 0 to 3, with a dilute caustic soda or sodium'carbonate solution. The salt solution is then separated off and the trichloroethylene is distilled off in vacuo. The produce obtained corresponds'in its properties to that of Example 1. but it surpasses it as to resistance to lime and acids.

Ewample 3 A solution of 100 parts of castor oil, in 300 parts of carbon tetrachloride is previously sulphonated by the action ofv 30 parts of sulphuric acid monohydrate at 30-40, whereby the sulphuric acid ester is formed, then the mass is cooled down to about 10 and at 10 to 3 55 parts of sulphur trioxide'are introduced in the following manner: Solidx bon tetrachloride is distilled off in vacuo.. The remaining product corresponds in its properties to that of Example 2.

I E wample 100 parts of-ricinoleic acid are dissolved in about 125 parts of trichlorpethylene and prevapor are introduced into the reaction mass which contains the sulphuric acid ester of ricinoleic acid. The mass is Worked up as described above. The product obtained may be evaporated to any degree of concentration. It corresponds in its properties to that of Example 1.

- E wample 5 Sulphur trioxide vapors are allowed to pass over a'solution of 100 parts of eastor oil in about 200 parts of carbon tetrachloride which is held at 10 to -3, until 25 parts of S0 are absorbed. Then the mass is poured on a small quantity of ice and at about 0 to 10 a caustic soda solution is added until a feeble acidrcaction is obtained. The salt solution is then separated off, the carbon tetrachloride is distilled off in Vacuo and the remaining yellowish oil shows Turkey red oil-like properties. i

We claim:

1. A process of sulphonating an unsaturated fatty acid'compound which comprises introducing gaseous sulphur trioxide into a solution of said unsaturated fatty acid compound in an organic diluent.

2. A process of sulphonating an unsatuk rated liydroxy fatty acid compound which comprises introducing gaseous sulphur trioxide into a solution of said unsaturated hydroxy fatty acid compound in an organic diluent at a low temperature.

3. A process of sulphonating an unsaturated fatty acid eompound which comprises introducing gaseous sulphur trioxide into a solution of said unsaturated fatty acid compound in an organic diluent at between about 10 to 3 0. a

4:. A process of sulphonating an unsaturated hydroxy fatty acid compound which comprises introducing into a solution of an unsaturated hydroxy fatty acid compound in an organic'diluent at between about 10 to 5. A' process of sulphonating castor oil which comprises introducing into a solution of castor oll n an organlc diluent at-between about 10 to -3 C., such an amount of gaseous sulphur trioxide as exceeds the amount suflicient .for esterifying the hydroxy groups.

In testimony whereof, we affix our signatures.

. GEO RG KALISOHER.

FRITZ GI'TNTHER KARL KELLER.

JOSEF HETZER. 

